Non-volatile resistance switching memory, particularly memory based on complex metal oxides, is typically either deposited at high temperature, usually at about 800° C., or requires high temperature post-deposition annealing. This makes it impossible to integrate this type of memory in a back end of the line (BEOL) process with standard complementary-metal-oxide-semiconductor (CMOS) technology. For far BEOL integration the allowed temperatures are even more stringent.
Liu et al., Electrical-pulse-induced reversible resistance change effect in magnetoresistive films, Applied Physics Letters, 76, 2749, 2000 and the international publication WO00/15882 relate to a perovskite layer deposited epitaxially (single crystalline) at elevated temperature by pulsed laser deposition on a substrate. This deposition technique cannot be used for standard CMOS technology.
US20030148545A1 shows a way of manufacturing a variable resistor device based on poly-crystalline perovskite metal oxides using spin-coating deposition techniques. Silicon substrates can be used with the techniques of manufacturing. An annealing process step of the spin-coated layer between 400° C. and 700° C. is however required to obtain switching between a first resistance state and a second resistance state in the respective devices.
From the above it follows that there is still a need in the art for a process for manufacturing resistance switching memory based on a complex metal oxide such that (far) BEOL integration with standard CMOS technology becomes possible.